In the related art, an optical transceiver that transmits and receives an optical signal by an optical fiber and the like is known. Further, as a configuration for a connection detecting function, a transmission device is known which includes a light emitting device for a connection detection, such as a light emitting diode emitting exited light including light of a predetermined wavelength (see, e.g., International Publication Pamphlet No. WO 2012/093431).
Related technologies are disclosed in, for example, International Publication Pamphlet No. WO 2012/093431.